| Term |
Definition |
| T Interface |
Terminal Interface, the minimal ISDN network termination at the customer premises. |
| T1 |
The highest-speed line commonly used to connect networks to the Internet, capable of carrying data at 1.5MB per second. A leased line that provides digital transmission. |
| T1 Robbed Bit |
Type of signaling used during T1 transmissions in which the D channel is buried with the B channels, using the least-significant bits. T1 Robbed Bit circuits provide a simple signaling mechanism between the customer premise equipment and the central office. Each side transmits one (sometimes two) signaling bits, which can be set to 0 or 1 to the other side; the status of the signaling bit corresponds to the status of the cell. |
| T3 |
A dedicated digital communication link provided by a telephone company that offers 44.75 megabits per second of bandwidth, commonly used for carrying traffic to and from private business networks and Internet service providers. |
| TACS |
Total Access Communications Systems. |
| Tail Circuit |
The connection from a satellite or microwave receiver to a user's equipment location. |
| TASI |
Time Assignment Speech Interpolation. |
| TC |
i. Transmission Convergence layer, ii.Temperature Coefficient. |
| TCAM |
Telecommunications Access Method. |
| TCP |
Transmission Control Protocol - A transport layer, TCP is a highly reliable host-to-host protocol that guarantees packet delivery, non-duplicated and in order. TCP runs on top of IP. Defined in IETF RFC791 & STD7. |
| TDM |
Time Dividion Multiplexing - TDM busses carry voice data divided according to frames. In a single 125 us frame, the TDM bus will have carried one byte from each channel it contains. |
| TDMA |
Time Division Multiple Access - a technology for delivering wireless service using time-division multiplexing (TDM). TDMA works by dividing a radio frequency into time slots and then allocating slots to multiple calls. In this way, a single frequency can multiple, simultaneous data channels.. |
| Telco |
A popular abbreviation for telephone company. |
| Telephony |
A term used to describe the process of the electronic transfer of voice communication. |
| Terabyte |
1,024 gigabytes, or 1,099,511,627,776 bytes. |
| Terminal Adapter |
In Integrated Service Digital Network technology an interface that links non ISDN compatible terminals to an ISDN service. |
| Thick Wire |
A term often used to describe standard (50 ohm) Ethernet/IEEE 802.3 cable. |
| Thin Wire |
A term often used to describe the 75 ohm co-axial cable used (and allowed in IEEE 802.3 specifications) in some Ethernet installations. |
| THz |
TeraHertz |
| TIA |
Telecommunications Industry Association. |
| Time Assignment Speech Interpolation |
A voice telephony mechanism whereby circuit use is activated by the actual presence of a speech signal. The result is the efficient use of transmission facilities. |
| Time Compression Multiplexer |
A form of Multiplexer which uses time compression techniques rather than time division. Used to allow high speed transmission over local loop facility. |
| Time Division Multiplexer |
The device which executes the process whereby more then one slow speed device can be made to share a high speed line by allowing each a time period on the line. |
| Time Interval Error |
The difference between a given timing signal and the ideal timing signal. |
| Time Slot |
The term time slot is often used to define a combination of a time slot and a stream on the H.100 bus. Thus a time slot would represent a single 8-bit slot every 125 us on the TDM bus. Time slot/Stream numbers are numbered 0 to 4095 according to the following equation: time slot * 32 + stream. On reduced-frequency TDM streams, certain time slots become unusable. For streams running on a 4 MHz clock, time slots are numbered 0 to 63, and the equations to determine TSSTs are the following: in the TX TDM, TSST = (time slot * 2 + 1) * 32 + stream, and in the RX TDM, TSST = (time slot * 2) * 32 + stream. In like manner, for streams running on a 2 MHz clock, time slots are numbered 0 to 31, and the equations are: in the TX TDM, TSST = (time slot * 4 + 3) * 32 + stream, and in the RX TDM, TSST = (time slot * 4) * 32 + stream. |
| Timing Signal |
A cyclic signal used to control the timing of operations. |
| Timing Slip |
A sudden timing delay change during high speed digital transmission. Often caused by the use of T1 carriers from different suppliers. |
| TOS |
Type of service. |
| Touch Tone |
The AT&T registered trademark for push-button dialing. The signal produced by each button is in the form of multiple frequencies or tones. |
| Transducer |
A device which converts the physical properties of a signal from one energy form to another. The attachment interface between a computer (electron based signals) to a fiber optic (photon based signals) transmission medium is an example. |
| Transit timing |
A method of eliminating looping between nodes. Used in the network layer of some packet switched systems. This method is used in the IP portion of TCP/IP. |
| Transmission |
The transfer of information from one point to another using one of many physical methods and one of many media. |
| Transparent bridge |
A transparent bridge discovers which MAC addresses are attached to each of its ports, and stores this information in tables that it updates. When a transparent bridge receives a frame, it checks to see which output port the frame's destination address is on, and transfers the frame onto that output port. |
| Transponder |
A device that receives a signal, amplifies it and retransmits it at a different frequency |
| TSI |
Time slot interchange. |
| Twisted Pair |
A transmission medium where two insulated wires are twisted together. This twisting creates a level of noise elimination. |
| Tx |
Transmit. |
